Wood granular activated carbon for automobile carbon canister and preparation method thereof

Abstract

The invention discloses wood particle active carbon for an automobile carbon tank and a preparation method thereof, and belongs to the fields of active carbon for the automobile carbon tank and the preparation method of the active carbon. The weight ratio of major raw material ingredient of wood active carbon powder to organic sodium-based bentonites to water is 1:(0.2 to 0.25):(0.8 to 1.0); the three kinds of raw materials are uniformly stirred and are then pelleted; after pelleted particles are dried, physical activation is performed to obtain the wood particle active carbon; the wood active carbon powder is formed by mixing aged wood chips and thermal-process food stage phosphoric acid with the concentration being 85 percent according to a weight ratio of 1:(1.2 to 1.5) through fully stirring, still soaking, high-temperature carbonization activation, recovery, rinsing, drying and powder preparation. The preparation method comprises two major work procedures of wood active carbon powder preparation and wood particle active carbon preparation. The product strength is high; the effective aperture pore volume is more developed; the distribution is more uniform; the adsorption and desorption performance is good; the gas flowing resistance is small.

Description

technical field [0001] The invention relates to the field of activated carbon for automobile canisters and a preparation method thereof, in particular to a wood granular activated carbon for automobile canisters which combines a chemical activation method and a physical activation method and a preparation method thereof. Background technique [0002] At present, with the increasingly stringent emission standards of automobiles and the mature application of automobile exhaust purification technology, the proportion of hydrocarbons in exhaust gas after fuel evaporation is gradually increasing in vehicle emissions. The carbon canister is a key component of gasoline vehicle fuel evaporation control, and its core material is shaped activated carbon for gasoline adsorption and desorption. The shaped activated carbon required by the carbon canister technology has a high specific surface area and high strength, requires an effective pore volume of 2-5mn, and must have the function o...

AI Technical Summary

Problems solved by technology

At present, the production process of activated carbon for automobile canisters used in the field of automobile production in my country is to use wood chips as raw materials, which are made by crushing, mixing, extrusion, drying, carbonization, and activation. The activated carbon produced in this way has the following defects : (1) The strength is low, because the wood chips are stirred and extruded with the chemical activator phosphoric acid, and then activated by high-temperature carbonization, and the wood chips will inevitably shrink and crack during the high-temperature carbonization activation after molding, and will occur during production. The mutual friction and collision between charcoal and charcoal will greatly reduce the strength of activated carbon. The product has low strength, uneven strength, severe powder loss, and is brittle.

(2) Poor adsorption and desorption performance, low service life

This production process of forming first and then carbonizing and activating cannot meet the production needs of high-quality formed activated carbon in the market, because activated carbon mainly produces effective pore size and pore volume in the process of carbonization and activation, that is to say, the more effective pore size and pore volume, the more The better the adsorption and desorption performance of developed activated carbon is, the existing traditional process is to adopt the production process of forming first and then activating. The product obtained by carbonization and activation, the product obtained by this production process, its pore structure and the distribution of pore size and pore volume are not uniform. It is found through the detection of pore structure and specific surface area analyzer that the surface pore diameter has 2 -7mn, the specific surface area is 1500㎡ / g, while the middle part of the particle is only 0.5-2mn, the specific surface area is only about 800; therefore, the activated carbon produced by the traditional process can only be adsorbed on the surface, and the activated carbon produced in this way only has the surface With a certain pore size and functional group, it is difficult to have a standard pore size and pore volume, so its performance and working capacity will be greatly reduced, resulting in short service life and poor performance.

(3) The gas flow resistance is large, because the more developed the pore size and pore volume of activated carbon, the less its gas flow resistance, and the above-mentioned production process only has a certain pore size and pore volume on the surface, and the middle of the carbon cannot get effective. Carbonization activation, resulting in no pore size and pore volume inside the carbon column, so it has a large flow resistance to gas, which is not conducive to the adsorption and desorption of volatile solvents by activated carbon, reducing the recycling rate